The present invention relates to a new and distinct hybrid variety of northern highbush blueberry (Vaccinium corymbosum L.) named ‘RYOKU NH-13’. This novel variety was found by open pollination of ‘Chandler’, a seed parent variety, in the tests conducted for the period from 2003 to 2007 in Matsumoto-City, Nagano-prefecture, Japan. As stated below, ‘RYOKU NH-13’ has apparently different characteristics from those of the varieties ‘Chandler’ and ‘Blueray’, both being widely planted and being important varieties in the Chubu district of Japan.